On this year's World Autism Awareness Day, held every April 2, Facebook's official charity page shared an image from actress Jenny McCarthy.
McCarthy and her organization, Generation Rescue, have faced scrutiny over the issue of childhood vaccinations.
McCarthy has claimed that vaccinations are responsible for the mysterious rise in autism spectrum disorders, noting that the current childhood vaccine schedule contains more vaccines than the schedule in the late 1990s.
But most experts agree there is no relationship between the mental condition and vaccines, and believe conspiracy theories about vaccinations endanger children's health. Children who are not vaccinated are at risk of catching preventable diseases like polio and whooping cough.
One Facebook user commented on the image: "You did not just share the anti Vax wacko post did you?"